Laminated cellulose ether-cellulose ester film



- LAMINATED CELLULQSE ETHE IR GELLULOSE ESTER FILM Filed Oct. 13, 1923 CeZZaZase 195281" @921 I INVENTOR, 02m M 110mm BY X13 1,,

4 ATTORJV'EI. I

Patented Dec. 9, i924.

JOHN M. nonun on, or nus'rrra, new sons, assreuoa no EASTMAN Roper; coniramz, or uocnmarn, new roan, A ,coaronarron or new roan.

IAMINATED CELEIULO$E ETHER-CELLULOSE ESTER FILM.

Application filed October 13,1923; Serial No. 688,411.

To all 107mm z't'vnag concern:

Be it known that 1, John M. Dorronun, a citizen of the United States of America, re siding at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Laminated Cellulose Ether-Cellulose Ester Films, of which the following is "a full, clear, and exact specification.

This invention relates to cellulose ether films and particularly those which are laminated with layers of cellulose'esters. One object of the invention is to provide a cellulose ether film of this character which maintains its'fiex' ility, even after prolongedheatingfiiiiderpoinparatively severe conditions. Another object of the invention is to maintain the flexibility by suitably increasing its infiammability. Other objects will hereinafter appear.

' In the accompanying drawing the single figure is a diagrammatic sectional view showing the elements of the film'on an exaggerated scale.

In U. S. Patent No. 1,188,376, Lilienfeld, June 20, 1916, there are disclosed a series of ethers of cellulose. Certain of these are practically insoluble in water, and the present invention finds its primary application with respect to others having that property, although it. is not restricted to them. When such others are made into films for different uses, such photographic supports. it is desirable, under circumstances which are often met with in practice, that they withstand a prolonged heating without becoming too brittle. ln testing such films to determine whether they will Withstand the conditions of practice, severe tests are customarily made by hcatingwthem for several weeks at a tcmpcrall'ire of (l. It is de sirablc that the films remain usefully flcx ible, even after twelve weeks of continuous heating at the above temperature.

I have (liscovcrcd that films oi cellulbsc other can withstand such a severe test it they be coated on each face witha layer, preferably but not necessarily a very thin one. of acellulose ester. such as nil'roceL lulose in the preferred form of my invention. The laminated structure is. of course, maintained by a firm adherence of the outer layers of cellulose ester to the inner layer of oelluloseether.

The cellulose ether layer, which is the main layer in my preferred product, may he made from any of the well known ether film-making compositions described in the prior patents in this art. The outer layers or coatings of cellulose ester may contain high boiling'plastifiers and'the like in con nection with the cellulosic compound. I

find, however, that a plain solution of nitrothe cellulose ether layer, whiled, l infill-- cate the layers of cellulose ester, such as cellulose nitrate.

Films produced as above indicated are not as inflammable as those composed entirely of nitrocellu lose, in" fact, preserve most of the advantageous properties of a film of cellulose etheig'and in addition have the unexpected stability with respect to flexibility when. heated for many weeks at (I. They malre excellent supports for light-sensitive photographic emulsions. lVhile cellulose acetate may be employed in place of cellulose nitratein the above err.- ample, the latter is preferable and more certain in its results on the stability.

Having thus described my invention, what- I claim as new and desire to secure by Let ters Patent is z" I 1. 'As an article of manufacture, a. cellulose other film,having on each face an adherent layer of cellulose ester, which layers. maintain flexibility in said film alter pr olo gedheating thereofat65 C. 

